IAsyncResult Interfaz

Definición

Espacio de nombres:

System

Ensamblado:

System.Runtime.dll

Ensamblado:

mscorlib.dll

Ensamblado:

netstandard.dll

Representa el estado de una operación asincrónica.

public interface class IAsyncResult

public interface IAsyncResult

[System.Runtime.InteropServices.ComVisible(true)]
public interface IAsyncResult

type IAsyncResult = interface

[<System.Runtime.InteropServices.ComVisible(true)>]
type IAsyncResult = interface

Public Interface IAsyncResult

Derivado

System.IdentityModel.AsyncResult

System.IdentityModel.Selectors.SecurityTokenProvider.SecurityTokenAsyncResult

System.Runtime.Remoting.Messaging.AsyncResult

System.Threading.Tasks.Task

System.Transactions.CommittableTransaction

System.Web.Services.Protocols.WebClientAsyncResult

Atributos

ComVisibleAttribute

Ejemplos

En el ejemplo siguiente se muestra cómo usar la AsyncWaitHandle propiedad para obtener un WaitHandley cómo esperar una llamada asincrónica en un delegado. WaitHandle se señaliza cuando finaliza la llamada asincrónica y puede esperar a que termine llamando al método WaitOne .

El ejemplo consta de dos clases: la clase que contiene el método al que se llama de forma asincrónica y la clase que contiene el Main método que realiza la llamada.

Para obtener más información y más ejemplos de llamada a métodos de forma asincrónica mediante delegados, vea Llamar a métodos sincrónicos de forma asincrónica.

using namespace System;
using namespace System::Threading;
using namespace System::Runtime::InteropServices; 

namespace Examples {
namespace AdvancedProgramming {
namespace AsynchronousOperations
{
    public ref class AsyncDemo 
    {
    public:
        // The method to be executed asynchronously.
        String^ TestMethod(int callDuration, [OutAttribute] int% threadId) 
        {
            Console::WriteLine("Test method begins.");
            Thread::Sleep(callDuration);
            threadId = Thread::CurrentThread->ManagedThreadId;
            return String::Format("My call time was {0}.", callDuration);
        }
    };

    // The delegate must have the same signature as the method
    // it will call asynchronously.
    public delegate String^ AsyncMethodCaller(int callDuration, [OutAttribute] int% threadId);
}}}

using System;
using System.Threading;

namespace Examples.AdvancedProgramming.AsynchronousOperations
{
    public class AsyncDemo
    {
        // The method to be executed asynchronously.
        public string TestMethod(int callDuration, out int threadId)
        {
            Console.WriteLine("Test method begins.");
            Thread.Sleep(callDuration);
            threadId = Thread.CurrentThread.ManagedThreadId;
            return String.Format("My call time was {0}.", callDuration.ToString());
        }
    }
    // The delegate must have the same signature as the method
    // it will call asynchronously.
    public delegate string AsyncMethodCaller(int callDuration, out int threadId);
}

Imports System.Threading
Imports System.Runtime.InteropServices 

Namespace Examples.AdvancedProgramming.AsynchronousOperations
    Public Class AsyncDemo 
        ' The method to be executed asynchronously.
        Public Function TestMethod(ByVal callDuration As Integer, _
                <Out> ByRef threadId As Integer) As String
            Console.WriteLine("Test method begins.")
            Thread.Sleep(callDuration)
            threadId = Thread.CurrentThread.ManagedThreadId()
            return String.Format("My call time was {0}.", callDuration.ToString())
        End Function
    End Class

    ' The delegate must have the same signature as the method
    ' it will call asynchronously.
    Public Delegate Function AsyncMethodCaller(ByVal callDuration As Integer, _
        <Out> ByRef threadId As Integer) As String
End Namespace

#using <TestMethod.dll>

using namespace System;
using namespace System::Threading;
using namespace Examples::AdvancedProgramming::AsynchronousOperations;

void main() 
{
    // The asynchronous method puts the thread id here.
    int threadId;

    // Create an instance of the test class.
    AsyncDemo^ ad = gcnew AsyncDemo();

    // Create the delegate.
    AsyncMethodCaller^ caller = gcnew AsyncMethodCaller(ad, &AsyncDemo::TestMethod);
       
    // Initiate the asychronous call.
    IAsyncResult^ result = caller->BeginInvoke(3000, 
        threadId, nullptr, nullptr);

    Thread::Sleep(0);
    Console::WriteLine("Main thread {0} does some work.",
        Thread::CurrentThread->ManagedThreadId);

    // Wait for the WaitHandle to become signaled.
    result->AsyncWaitHandle->WaitOne();

    // Perform additional processing here.
    // Call EndInvoke to retrieve the results.
    String^ returnValue = caller->EndInvoke(threadId, result);

    // Close the wait handle.
    result->AsyncWaitHandle->Close();

    Console::WriteLine("The call executed on thread {0}, with return value \"{1}\".",
        threadId, returnValue);
}

/* This example produces output similar to the following:

Main thread 1 does some work.
Test method begins.
The call executed on thread 3, with return value "My call time was 3000.".
 */

using System;
using System.Threading;

namespace Examples.AdvancedProgramming.AsynchronousOperations
{
    public class AsyncMain
    {
        static void Main()
        {
            // The asynchronous method puts the thread id here.
            int threadId;

            // Create an instance of the test class.
            AsyncDemo ad = new AsyncDemo();

            // Create the delegate.
            AsyncMethodCaller caller = new AsyncMethodCaller(ad.TestMethod);

            // Initiate the asychronous call.
            IAsyncResult result = caller.BeginInvoke(3000,
                out threadId, null, null);

            Thread.Sleep(0);
            Console.WriteLine("Main thread {0} does some work.",
                Thread.CurrentThread.ManagedThreadId);

            // Wait for the WaitHandle to become signaled.
            result.AsyncWaitHandle.WaitOne();

            // Perform additional processing here.
            // Call EndInvoke to retrieve the results.
            string returnValue = caller.EndInvoke(out threadId, result);

            // Close the wait handle.
            result.AsyncWaitHandle.Close();

            Console.WriteLine("The call executed on thread {0}, with return value \"{1}\".",
                threadId, returnValue);
        }
    }
}

/* This example produces output similar to the following:

Main thread 1 does some work.
Test method begins.
The call executed on thread 3, with return value "My call time was 3000.".
 */

Imports System.Threading
Imports System.Runtime.InteropServices 

Namespace Examples.AdvancedProgramming.AsynchronousOperations

    Public Class AsyncMain 
        Shared Sub Main() 
            ' The asynchronous method puts the thread id here.
            Dim threadId As Integer

            ' Create an instance of the test class.
            Dim ad As New AsyncDemo()

            ' Create the delegate.
            Dim caller As New AsyncMethodCaller(AddressOf ad.TestMethod)
       
            ' Initiate the asynchronous call.
            Dim result As IAsyncResult = caller.BeginInvoke(3000, _
                threadId, Nothing, Nothing)

            Thread.Sleep(0)
            Console.WriteLine("Main thread {0} does some work.", _
                Thread.CurrentThread.ManagedThreadId)
            ' Perform additional processing here and then
            ' wait for the WaitHandle to be signaled.
            result.AsyncWaitHandle.WaitOne()

            ' Call EndInvoke to retrieve the results.
            Dim returnValue As String = caller.EndInvoke(threadId, result)

            ' Close the wait handle.
            result.AsyncWaitHandle.Close()

            Console.WriteLine("The call executed on thread {0}, with return value ""{1}"".", _
                threadId, returnValue)
        End Sub
    End Class
End Namespace

'This example produces output similar to the following:
'
'Main thread 1 does some work.
'Test method begins.
'The call executed on thread 3, with return value "My call time was 3000.".

Comentarios

La IAsyncResult interfaz se implementa mediante clases que contienen métodos que pueden funcionar de forma asincrónica. Es el tipo de valor devuelto de métodos que inician una operación asincrónica, como FileStream.BeginRead, y se pasan a métodos que concluyen una operación asincrónica, como FileStream.EndRead. IAsyncResult Los objetos también se pasan a los métodos invocados por AsyncCallback delegados cuando se completa una operación asincrónica.

Un objeto que admite la IAsyncResult interfaz almacena información de estado para una operación asincrónica y proporciona un objeto de sincronización para permitir que los subprocesos se señalen cuando se complete la operación.

Nota

La AsyncResult clase es la implementación de IAsyncResult que devuelve el BeginInvoke método cuando se usa un delegado para llamar a un método de forma asincrónica.

Para obtener una descripción detallada de cómo se usa la IAsyncResult interfaz, consulte el tema Llamar a métodos sincrónicos de forma asincrónica .

Propiedades

AsyncState	Obtiene un objeto definido por el usuario que califica o contiene información sobre una operación asincrónica.
AsyncWaitHandle	Obtiene WaitHandle que se utiliza para esperar a que finalice una operación asincrónica.
CompletedSynchronously	Obtiene un valor que indica si se completó la operación asincrónica de forma sincrónica.
IsCompleted	Obtiene un valor que indica si se completó la operación asincrónica.